How to make a flat vdmos

Abstract

The invention provides a planar VDMOS manufacturing method. The planar VDMOS manufacturing method comprises the steps of: growing a thin oxidation layer on the surface of an epitaxial layer; defining a loop region through photoetching and etching processes, and carrying out ion implantation under the thin oxidation layer on the surface of the loop region, wherein the etching depth is less than the thickness of the thin oxidation layer; carrying out ion drive-in in the loop region to form a first region in the surface of the epitaxial layer under the loop region, and growing an oxidation layer on the surface of the thin oxidation layer continuously to form a thick oxidation layer; defining an active region, and etching out the thick oxidation layer in the active region; growing a gate oxidation layer on the surface of the active region, and forming polysilicon gates on the gate oxidation layer; and forming a body region through self-aligned implantation and drive-in, defining source regions, and completing ion implantation and drive-in, wherein the body region surrounds the source regions, partial regions of the body region and the source regions extend below the polysilicon gates, and the depth of the body region is less than that of the first region. The planar VDMOS manufacturing method only needs two long-time high-temperature heat treatment processes, reduces cost and shortens manufacturing period.

Description

technical field [0001] The invention relates to the field of semiconductor chip manufacturing, in particular to a method for manufacturing planar VDMOS. Background technique [0002] Vertical double-diffused field-effect transistor (VDMOS) is one of the most commonly used power transistors at present. As a voltage-controlled device, the gate voltage signal controls the formation of the channel, thereby controlling the conduction of the source and drain currents. VDMOS has the advantages of both bipolar transistors and ordinary MOS devices, and is widely used in the field of switching power supplies. [0003] The traditional planar VDMOS fabrication method is as follows: [0004] Step 1. Initially oxidize a thick oxide layer on the epitaxial layer. The thickness of the thick oxide layer is generally greater than 10,000 angstroms, the oxidation temperature is between 1050-1200 degrees, and the oxidation time is between 250-400 minutes; [0005] Step 2, define the ring area b...

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Problems solved by technology

[0013] The invention provides a method for manufacturing planar VDMOS, which is used to solve the problems of high production cost and long production cycle in the prior art

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